The present disclosure relates to refrigeration compressors. More particularly, it relates to displacement compressors (e.g., reciprocating piston compressors) utilized to compress gases such as low global warming potential (GWP) and natural refrigerants.
In a reciprocating compressor a piston head is driven between a lower position at which a fluid to be compressed enters the compression cylinder, and an upper or “top” position at which the compressed fluid is driven outwardly of the cylinder. A valve plate is typically placed at the top of the cylinder. The term “top” and “bottom” do not mandate any relative or absolute vertical orientation, but instead only to a relative position in the cylinder. The valve plate carries both inlet (suction) and outlet (discharge) valves for allowing the flow of fluid into the cylinder, and out of the cylinder at appropriate points in the reciprocating movement of the piston. In reciprocating piston compressors and the like, pressure-actuated valves typically open and close once during each shaft revolution of the compressor.
Various types of valves are known, and various types of valve plates have been utilized. One type of compressor valving structure uses reed valves. A reed valve may cover a plurality of circumferentially spaced ports. When the valve closes, it contacts the valve seat due to valve stiffness and/or pressure actuation, thus sealing flow out of the cylinder for the suction valve, or into the cylinder for the discharge valve.
A recent compressor configuration having reed valves for suction and discharge purposed is seen in U.S. Ser. No. 61/696,729, filed Sep. 4, 2012. Such compressors protect the discharge reeds against overflexing via a rigid backer. Such a backer has a generally convex (convexity about transverse axes when viewed in a longitudinal section) underside complementary to a concave outboard/upper face of the reed in a maximum desired open condition.